Characterization of Leptazolines A-D, Polar Oxazolines from the Cyanobacterium sp., Reveals a Glitch with the "Willoughby-Hoye" Scripts for Calculating NMR Chemical Shifts.

The bioactivity-guided examination of a sp. led to the isolation of leptazolines A-D (-), from the culture media, along with two degradation products ( and ). Density functional theory nuclear magnetic resonance calculations established the relative configurations of and and revealed that the calculated shifts depended on the operating system when using the "Willoughby-Hoye" Python scripts to streamline the processing of the output files, a previously unrecognized flaw that could lead to incorrect conclusions.